Refrigeration



8- 1944- 'r. K. SHERWOOD 2,354,884

REFRIGERATION Filed April 25, 1941 m 58 a I I 45 56 e0 57 i i 59 INVENTOR 4s 55 7:;

-04? 1 1 1 ATTORNEY Patented Aug. 1, 1944 2,354,884 REFRIGERATION Thomas K. Sherwood, Wellesley Hills, Mass., assignor to Servel, Inc., New York, N. Y., a corporation of Delaware Application April 25, 1941, Serial No. 390,257

15 Claims.

My invention relates to refrigeration and more particularly to heat -operated refrigeration systems.

It is an object of the invention to provide a refrigeration system employing a small heat input. This is accomplished by utilizing a solution which when heated has the property of separating into its components which stratify. Fluid drawn from one stratum is evaporated to produce a refrigerating effect, and the resulting vapor is absorbed in fluid drawn from the other stratum.

In the drawing:

Fig. 1 shows more or less diagrammatically a two-pressure refrigeration system embodying the invention; and

Fig. 2 shows more or less diagrammatically a uniform pressure refrigeration system embodying the invention.

Referring to Fig.1, the system includes an evaporator I and an absorber II. The absorber I5, and a separator I6. Heater I4 is shown in the form of a coil heated by a burner II. 'Receiver- I5 is provided with a reflux condenser I8 comprising a finned co'il connected at both ends to the receiver. The upper end of heater I4 is connected by a conduit I9 to receiver I5. The bottom of receiver I5 is connected by a conduit 20 to the separator vessel I6. Separator I6 is located at a level below that of the receiver I5, and conduit 20 is connected to separator I6 substantially midway of the top and bottom thereof.

The upper part of separator I6 is connected by a conduit 2|, 2. liquid heat exchanger 22, and a conduit 23 to evaporator III. A pressure reducing or expansion valve 24 is connected in this line between the separator and evaporator. It is shown connected in conduit 2 I. The lower part of separator I6 is connected by a conduit 25, a heat exchanger 26, and a conduit 21 to the upper part of absorber II. A pressure reducing or expansion valve 28 is connected in this line between the separator and absorber. It is shown connected in conduit 25.

The bottom of absorber II is connected by a conduit 23, heat exchanger 26, a conduit 30, heat exchanger 22, and conduit 3| to the lower end of heater coil I4. Evaporator III is connected by a conduit 32 to conduit 30. Conduit 32 is connected to evaporator. III at a point above the bottoin of the evaporator so as to act as an overflow conduit I3 into absorber II.

for liquid from the evaporator. A liquid pump 331s connected in conduit 3| in a manner to cause flow of liquid through this conduit in the directionof heater I4. If desired, a vent conduit, not shown, may be connected between the top of separator I6 and the top of receiver I5.

The system just described is evacuated and charged with a solution which stratifies upon increase in temperature as, for example, a solution of water and triethylamine. Water solutions of diethylamine or methyldiethylamine may also be used.

Pump 33 causes flow of the solution of water and triethylamine through heater I4 and conduit I9 into receiver I5. When burner I1 is operating, the solution is heated in coil I4. Any vapor that may be formed due to this heating enters condenser I8 from receiver I5. The vapor condenses to liquid in condenser I8 and flows back into receiver I5. The heated solution flows from receiver I5 through conduit 20 into separator I6. At the higher temperature due to the described heating of the solution, the Water and triethyl- --lighter layer, consisting principally of triethylamine flows from the upper part of separator I6 through conduit 2 I liquid heat exchanger 22, and conduit 23 into evaporator I0. Liquid from the heavier layer, consisting principally of water, flows from separator I6 through conduit 25, heat exchanger 26 and conduit 21 into the top of absorber I I. The triethylamine evaporates in evaporator IIl, producing a refrigerating effect. The resulting vapor flows from evaporator Ill through Water flows downward over baflle plates 34 in absorber II and absorbs the vaporous triethylamine, thus reforming the solution. This solution flows from the absorber through conduit 29, heat exchanger 26, conduit 30, heat exchanger 22, and conduit 3| back to heater I4, this flow being part of the circulation caused by pump 33. Any excess liquid in evaporator I0 overflows through conduit 32 and joins the solution in conduit 30.

Whatever combination of fluids is used, the fluid having the higher vapor pressure at low temperature is used as the refrigerant, and the other fluid which has the lower vapor-pressure is used as the absorbent. Both fluids have substantially the same vapor pressure at the high temperature at which they are separated by stratiflcation. Also, whatever combination of fluids is used, the heavier fluid is drawn from the bottom of the separator and the lighter fluidfrom the top.

Referring to Fig. 2, the system includes an evaporator 46 and an absorber 4|. Absorber 4| is shown provided with a liquid cooling coil 42.

,Other means such as air may be used for cooling the absorber. The top of absorber 4| is connected to the top of evaporator 46 by a conduit 43. The lower part of evaporator 46 is conected by a conduit 44 to the lower part of absorber 4|. Conduits 43 and 44 are arranged in heat exchange relation.

This system also includes a heater 45, a receiver 46, and a separator 41. Heater 45 is shown as a coil heated by a burner 46. An air cooled reflux condenser 46 is connected to receiver 46. The upper end of heater coil 45 is connected by a vapor lift conduit 56 to receiver 46. The bottom of receiver 46 is connected by a conduit 5| to separator 41 about midway the height thereof.

The upper part of separator 41 is connected by a conduit 52, a liquid heat exchanger 53, and a conduit 54 to the upper part of evaporator 46. The lower part of separator 41 is connected by a conduit 55, a liquid heat exchanger 56, and a conduit 51 to the upper part of absorber 4 I Conduit 55 is provided with an upward loop, the top of this loop being enlarged and located on the same level as the upper end of conduit 52. The bottom of absorber 4| is connected by a conduit 58, heat exchanger 56, conduit 56, heat exchanger 53, and a conduit 66 to the lower end of heater coil 45. The top of loop 55 and the top of separator 41 may, if desired, be vented to the upper part of receiver 46 by conduits not shown.

The system described in connection with Fig. 2 is charged similarly to that described in connection with Fig. 1 except that there is also added an auxiliary inert fluid such as hydrogen.

When burner 48 is operating, the water solution of triethylamine is heated in coil 45 so that vapor is formed. This vapor flows upward through lift conduit 56, causing upward flow of liquid through this conduit into receiver 46. Vapor which enters receiver 46 flows into con+ denser 49. Vapor is condensed to liquid in condenser 46 and the liquid flows back into receiver 46. Liquid flows from-receiver 46 through conduit- 6| into separator 41. For the reason previously explained, triethylamine floats on top of the water in separator 41. g

Triethylamine flows from separator 41 through conduit 52, liquid heat exchanger 53, and conduit 54 into the upper partof evaporator 46. Water flows from separator'41 through conduit 55, heat onduit 51 into the top of absorber 4|. Ingevaporator 46, the refrigerant liquid flowsdownward over baffle plates 6| and evaporates and diffuses into the hydrogen, pro ducing a refrigerating effect. The resulting mixture of vapor and gas flows from the evaporator through conduit 44 to the absorber. Conduit 44\ also serves as a drain for unevaporated liquid from evaporator 46. Water flows downward over bailie plates 62 in the absorber and absorbs vaporous triethylamine, reforming the solution. The hydrogen gas flows from the absorber through conduit" back to the evaporator. The solution flows from the absorber through conduit 56, heat exchanger 56, conduit 56, heat exchanger 53, and conduit 66 back to the' heater 45.

The invention as described above is subject to other changes and modifications as known in the art and is therefore not limited except as indicated in the following claims.

What'isclaimed is:

1. A refrigeration system containing a solution having the property of stratifying into its component liquids upon increase in temperature and including means for heating said solution to cause said stratification, an evaporator, an absorber, and means to direct one of said component liquids to said evaporator and another of said liquids to said absorber.

2. A refrigeration system including an evaporator, an absorber connected to receive vapor from said evaporator, a heater connected to receive liquid from said absorber, a separator vessel connected to receive liquid from said heater, said system containing liquids which are mutually soluble at a first temperature and immiscible at a higher temperature so that said liquids stratify in said separator, and conduits for conducting one of said liquids from said separator to said evaporator, and another of said liquids from said sepa-' rator to said absorber.

3. A system as in claim 2 in which said liquids are water and one of the group consisting of triethylamine, diethylamine, and methyldiethylamine.

4. A refrigeration ystem including an evaporator, an absorber connected to receive vapon from said evaporator, a liquid circuit including said absorber, a heater, and a separator vessel, means for conducting liquid from said vessel to said circuit, said system containing liquids which are mutually soluble at a first temperature and immiscible at a higher temperature so that they separate by Stratification in said separator.

5. A system as in claim 4 which also includes a reflux condenser for reliquifying any vapor that may be formed due to said heater.

6. A system as in claim 4 in which said means for causing circulation of liquid in said circuit is a pump, and flow of liquid to said absorber and to said evaporator takes place through pressurevapor from said lift.

9. A system as in claim 4 in which said absorber is connected to receive vapor from said evaporator by means of an inert gas circuit in which they are included, and said means for causing circulation of liquid in said liquid lift.

10. A refrigeration system including an evaporator, an absorber, a conduit for vapor from said evaporator to'said absorber, a heater, a conduit for liquid from said absorber to said heater. a pump in last said conduit to cause flow of liquid circuit is a vapor therethrough, a separator connected to receive.

liquid from said heater, a conduit from said separator to said evaporator, a conduit from said separator to said absorber, and pressure reducing means in each of said last two conduits, said system containing liquids which are mutually soluble at a first temperature and immiscible at a higher temperature, whereby these liquids separate by Stratification in the separator and separately flow to said evaporator and absorber.

11. A refrigeration system including an evaporator, an absorber, conduits interconnecting said evaporator and absorber to form a circuit for inert gas, a heater, a conduit for liquid from said absorber to said heater, a separator, conduits including a vapor liquid lift for conducting liquid from said heater to said separator, a reflux condenser for liquifying vapor from said lift, and conduits connecting said separator for flow of liquid therefrom to each of said evaporator and absorber, said system containing liquids which are mutually soluble at a first temperature and immiscible at a higher temperature so that said liquids separate by stratification in said separator .and flow separately to said evaporator and absorbei'.

12. A refrigeration system containing liquids which are mutually soluble at a first temperature and immiscible at a higher temperature and in cluding means for heating said liquids to cause separation thereof by stratification, an evapseparated fluids to produce refrigeration, and absorbing the resulting vapor into another of said separated fluids to reform said solution.

14. A method of refrigeration which consists in evaporating one of the group vconsisting of triethylamine, diethylamine, and methyldiethylamine to produce a refrigerating 'efiect, absorbing the resulting vapor into water, and heating the resulting solution tocause separation of the water and ethylamine by Stratification to be again used in the evaporation and absorption steps,

15. A method of refrigeration which includes evaporating liquid refrigerant to produce a refrigerating effect, absorbing resulting vapor into a liquid absorbent, said liquid refrigerant and liquid absorbent-being mutually soluble at the temperature of absorption but immiscible at a higher temperature, and heating the solution to said higher temperature to cause separation of the refrigerant and absorbent by stratification for use again in said evaporation and absorption steps.

THOMAS K. SHERWOOD; 

